It is often desirable to eliminate or reduce the growth of grass or weeds about the base of a post, such as a generally upright post, or about the base of a tree or shrub. The elimination of such grass or weeds about the base eliminates the need for trimming the grass or weeds about the base and avoids damage to the base of the post from lawn mowers, weed-cutting apparatuses and the like. The growth of grass or weeds about the base of the post or tree can be controlled by eliminating the sunlight through the employment of a covered area about the base of the post or tree.
Therefore, it is desirable to provide for a tree-or post-collar apparatus and method which is inexpensive, easily assembled and used and is reusable and which may be adjusted to encircle the post or irregular tree-stem trunk, to eliminate the growth of grass or weeds about the base covered by the post collar, and which can expand to accommodate tree-trunk growth.